X-ray detector arrays may be used for various applications for detecting X-rays transmitted through a body, for example in medical imaging. A typical type of X-ray detector array used in CT scanners comprises a scintillator pack in which a multiplicity of scintillators is arranged as an array of scintillator pixels. The scintillators may be in the form of crystals, or ceramic scintillators, or composite scintillators. X-ray radiation entering one of the scintillator pixels generates scintillation radiation, for example, light in the visible spectral range. This light is detected using an array of associated photo detectors, arranged adjacent to the scintillator pixels. A photo detector may be associated with each of the scintillator pixels. When an x-ray photon is absorbed, the light is emitted omni-directionally by the scintillator, and all the surfaces of the scintillator element except that directed to the photo detector are therefore covered with a reflecting layer, which is generally a white powder incorporated in a resin, to direct that light into the photo detector. To reflect efficiently, this reflecting layer must be quite thick.
The array of photo detectors may be connected to an electronic circuit which serves, for example, for amplification, digitisation and/or multiplexing of electrical signals from the detector array.
Typically, not all of the x-rays incident upon the scintillator pack are absorbed. Residual X-radiation may be transmitted not only through the scintillator pixels themselves, but especially through the reflective layer in the inter-scintillator regions between them. This irradiation may be harmful to underlying electronic circuits.
A conventional scintillator is described in U.S. Pat. No. 7,310,405 B2. Therein, the reflective layer disposed in the inter-scintillator regions between the scintillator pixels comprises an X-ray absorbing material. The X-ray absorbing layer acts to absorb X-rays thereby protecting underlying regions of the inter-scintillator regions.